On the Origin of Species by Means of Natural Selection: Or The Preservation of Favoured Races in the Struggle for LifeHumphrey Milford, Oxford University Press, 1923 - 454 páginas |
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Página 5
... namely , first , the difficulties of transi- tions , or in understanding how a simple being or a simple organ can be changed and perfected into a highly developed being or elaborately constructed organ ; secondly , the subject of ...
... namely , first , the difficulties of transi- tions , or in understanding how a simple being or a simple organ can be changed and perfected into a highly developed being or elaborately constructed organ ; secondly , the subject of ...
Página 13
... namely , that our domestic varieties , when run wild , gradually but certainly revert in character to their aboriginal stocks . Hence it has been argued that no deductions can be drawn from domestic races to species in a state of nature ...
... namely , that our domestic varieties , when run wild , gradually but certainly revert in character to their aboriginal stocks . Hence it has been argued that no deductions can be drawn from domestic races to species in a state of nature ...
Página 21
... namely , that all have de- scended from the rock - pigeon ( Columba livia ) , including under this term several geographical races or sub- species , which differ from each other in the most trifling respects . As several of the reasons ...
... namely , that all have de- scended from the rock - pigeon ( Columba livia ) , including under this term several geographical races or sub- species , which differ from each other in the most trifling respects . As several of the reasons ...
Página 25
... namely , the improbability of man having formerly got seven or eight supposed species of pigeons to breed freely under domestica- tion ; these supposed species being quite unknown in a wild state , and their becoming nowhere feral ...
... namely , the improbability of man having formerly got seven or eight supposed species of pigeons to breed freely under domestica- tion ; these supposed species being quite unknown in a wild state , and their becoming nowhere feral ...
Página 26
... namely , that all the breeders of the various domestic animals and the cultivators of plants , with whom I have ever conversed , or whose treatises I have read , are firmly convinced that the several breeds to which each has attended ...
... namely , that all the breeders of the various domestic animals and the cultivators of plants , with whom I have ever conversed , or whose treatises I have read , are firmly convinced that the several breeds to which each has attended ...
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Términos y frases comunes
accumulated adapted affinities allied species America amount analogous ancient appear Archipelago become bees believe birds breeds cause cells characters cirripedes climate closely allied colour common parent continuous crossed crustaceans degree difficulty distinct species divergence doubt embryo endemic Europe existing exterminated extinct extremely facts favourable fertility flowers formations forms fossil Gärtner genera genus geological geological period Glacial period gradations greater number groups of species habits Hence hermaphrodites hybrids hybrids produced important individuals inhabitants inherited insects instance instincts intercrossing land larvæ less living male mammals manner Marsupials migration modification modified descendants natural selection naturalists nearly nest oceanic islands offspring organisation perfect pigeons pistil plants pollen present principle probably produced progenitor ranked reciprocal crosses remarked resemble rock-pigeon rudimentary organs seeds sexual selection Silurian slight South America sterility structure struggle successive suppose swimbladder tend theory tion trees variability variation vary whole widely